This invention relates to a data recording and/or reproducing apparatus, and more particularly is suitable to apply a computer external memory and the like, for example.
In a magnetic tape recording and reproducing apparatus of this kind, proposed hitherto is the so-called ID-1 format data recorder (ANSI.times.3.175-1990 19 mm Type ID-1 Recorded Instrumentation), wherein recording tracks are formed obliquely in sequence on a magnetic tape, and thus desired data can be recorded and reproduced in high density.
That is, as shown in FIG. 1, in such data recorder, a magnetic tape I is wound on a rotary drum rotating at a predetermined speed, the magnetic tape 1 is run at a predetermined speed, thereby forming recording tracks TR (. . . TR1, TR2, TR3, TR4, TR1, TR2, . . . ) obliquely in sequence by the magnetic head mounted on the rotary drum, and thus desired data is recorded on the recording track TR1.
Further in this case, the data recorder forms recording tracks TA, CTL and TC extending longitudinally on both upper and lower ends of the magnetic tape 1, and a track set identification (ID) of the recording tracks TR is recorded on the recording track CTL.
Here the track set identification (ID) i the absolute position information beginning from the first of the magnetic tape 1, put between predetermined synchronizing signals, and is recorded at a 4-track period with reference to the recording tracks TR.
Further the recording tracks TA and TC are ready for recording user's controlling data and others, thus data recorded in high density on the recording tracks TR can be searched simply by reproducing the recording tracks TA, CTL and TC.
Further in the data recorder, when recording data on the recording tracks TR, an error detecting/correcting parity code comprising the so-called product code is applied to record the data concerned, thereby recording and reproducing desired data securely.
That is, as shown in FIG. 2, after loading in data DATA in a predetermined unit (=36,108[BYTE]), the data recorder divides the data DATA into 306 blocks, and applies Reed-Solomon error detecting/correcting code (comprising C2 code) at each block.
Further, after dividing the block into a first field FIELD0 and a second field FIELD1, the data recorder applies Reed-Solomon error detecting/correcting code (comprising C1 code) so as to come orthogonal with the C2 code.
Thus in the data recorder, a bit error rate can be enhanced by correcting erroneous reproducing data by means of the C1 and C2 codes in reproducing.
Further in the data recorder, when recording the data DATA with the C1 and C2 codes applied thereto in the magnetic tape 1, interleaving is effected at every recording tracks TR, thus where a drop-out or the like arises, the data DATA can be reproduced securely.
That is, in the data recorder, with reference to the data DATA inputted in the order indicated by arrows al, a2, ..., an-1, an, an+l, an+2, ..., ax-1 and ax, the data DATA is recorded by changing the inputting order as indicated by arrows b1, b2, . . . , bn-1 and bn, thereby interleaving the data DATA.
Further in the data recorder in this case, a synchronizing signal SYNC and sync block data ID are added at every predetermined unit (hereinafter called sync block), and preamble and postamble data are added as a whole to record the data DATA.
Thus in reproducing, in the magnetic recording and reproducing apparatus, the synchronizing signal SYNC, the sync block data ID and the data DATA are reproduced on the basis of track sync data included in the preamble, and subjected to deinterleaving on the basis of the synchronizing signal SYNC and the sync block data ID.
Further from interleaving, an error exceeding an error correcting capacity of the C1 and C2 codes is prevented from concentrating into one spot effectively even in case drop-out or the like has arisen.
Meanwhile, in the ID-1 format data recorder for reproducing desired data as described above, a bit error rate 10.sup.-10 which is sufficient practically as the data recording and reproducing apparatus intended mainly for measurement is ensured.
If the bit error rate can be enhanced to 10.sup.-15 or so, then it is conceivable that important data may be safedeposit from applying to a magnetic tape recorder for computer system working, for example, in banks or the like.
Accordingly, a serviceability of this kind of data recorder will be enhanced to expand the applicable field.